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Physical spacetime geometry follows from some effective thermodynamics of quantum states of all fields and particles described in frames of General Relativity. In the sense of pure field theoretical Einstein's point of view on gravitation…

General Relativity and Quantum Cosmology · Physics 2008-08-27 L. A. Glinka

We study the classical and quantum models of a Friedmann-Robertson-Walker (FRW) cosmology, coupled to a perfect fluid, in the context of the scalar-metric gravity. Using the Schutz' representation for the perfect fluid, we show that, under…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Babak Vakili

In this paper we study quantum dynamics of the bouncing cosmological model. We focus on the model of the flat Friedman-Robertson-Walker universe with a free scalar field. The bouncing behavior, which replaces classical singularity, appears…

General Relativity and Quantum Cosmology · Physics 2013-06-12 Jean Pierre Gazeau , Jakub Mielczarek , Wlodzimierz Piechocki

The Moyal equation describes the evolution of the Wigner function of a quantum system in the phase space. The right-hand side of the equation contains an infinite series with coefficients proportional to powers of the Planck constant. There…

Quantum Physics · Physics 2023-08-01 E. E. Perepelkin , B. I. Sadovnikov , N. G. Inozemtseva , E. V. Burlakov , P. V. Afonin

We employ recently developed approximation methods in the hybrid quantization of the Gowdy $T^3$ model with linear polarization and a massless scalar field to obtain physically interesting solutions of this inhomogeneous cosmology. More…

General Relativity and Quantum Cosmology · Physics 2015-06-22 Beatriz Elizaga Navascués , Mercedes Martín-Benito , Guillermo A. Mena Marugán

A cosmological model describing the evolution of n Ricci-flat spaces (n>1) in the presence of 1-component perfect-fluid and minimally coupled scalar field is considered. When the pressures in all spaces are proportional to the density, the…

High Energy Physics - Theory · Physics 2009-09-25 V. D. Ivashchuk , V. N. Melnikov

We explore at phenomenological level a model of the Universe filled with various kinds of matter characterized by different equations of state. We show that introducing of each kind of matter is equivalent to a certain choice of a gauge…

General Relativity and Quantum Cosmology · Physics 2007-05-23 T. P. Shestakova

The metaplectic covariance for all forms of the Weyl-Wigner-Groenewold-Moyal quantization is established with different realizations of the inhomogeneous symplectic algebra. Beyond that, in its most general form $W_{\infty}$ -covariance of…

Quantum Physics · Physics 2009-10-31 A. Vercin

We review the main features of the Weyl-Wigner formulation of noncommutative quantum mechanics. In particular, we present a $\star$-product and a Moyal bracket suitable for this theory as well as the concept of noncommutative Wigner…

High Energy Physics - Theory · Physics 2008-11-26 C. Bastos , O. Bertolami , N. C. Dias , J. N. Prata

Bouncing models are alternatives to inflationary cosmology that replace the initial Big-Bang singularity by a `bouncing' phase. A deeper understanding of the initial conditions of the universe, in these scenarios, requires knowledge of…

General Relativity and Quantum Cosmology · Physics 2021-05-27 Karthik Rajeev , Vikramaditya Mondal , Sumanta Chakraborty

We consider quantum phase-space dynamics using Wigner's representation of quantum mechanics. We stress the usefulness of the integral form for the description of Wigner's phase-space current~$\bm J$ as an alternative to the popular Moyal…

Quantum Physics · Physics 2017-03-08 Dimitris Kakofengitis , Maxime Oliva , Ole Steuernagel

A free massless scalar field is coupled to homogeneous and isotropic loop quantum cosmology. The coupled model is investigated in the vicinity of the classical singularity, where discreteness is essential and where the quantum model is…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Martin Bojowald , Franz Hinterleitner

In the background of homogeneous and isotropic flat FLRW space-time, both classical and quantum cosmology has been studied for teleparallel dark energy (DE) model. Using Noether symmetry analysis, not only the symmetry vector but also the…

General Relativity and Quantum Cosmology · Physics 2024-07-12 Dipankar Laya , Roshni Bhaumik , Sourav Dutta , Subenoy Chakraborty

A fluid analog of the information flux in the phase-space associated to purity and von Neumann entropy are identified in the Weyl-Wigner formalism of quantum mechanics. Once constrained by symmetry and positiveness, the encountered…

Quantum Physics · Physics 2018-01-17 Alex E. Bernardini , Orfeu Bertolami

States of nonlinear quantum oscillators (f-oscillators) are considered in the Weyl-Wigner-Moyal representation and the tomographic probability representation, where the states are described by standard probability distributions instead of…

Quantum Physics · Physics 2015-05-14 Vladimir I. Man'ko , Giuseppe Marmo , Francesco Zaccaria

We discuss the fate of classical type IV singularities in quantum cosmology. The framework is Wheeler-DeWitt quantization applied to homogeneous and isotropic universes with a perfect fluid described by a generalized Chaplygin gas. Such a…

General Relativity and Quantum Cosmology · Physics 2014-03-12 Mariam Bouhmadi-Lopez , Claus Kiefer , Manuel Kraemer

The initial singularity is the most troubling feature of the standard cosmology, which quantum effects are hoped to resolve. In this paper, we study quantum cosmology with conformal (Weyl) invariant matter. We show it is natural to extend…

General Relativity and Quantum Cosmology · Physics 2017-05-24 Steffen Gielen , Neil Turok

The Weyl-Wigner representation of quantum mechanics allows one to map the density operator in a function in phase space - the Wigner function - which acts like a probability distribution. In the context of statistical mechanics, this…

Quantum Physics · Physics 2023-08-31 Marcos Gil de Oliveira , Alfredo Miguel Ozorio de Almeida

Inspired from the idea of minimally coupling of a real scalar field to geometry, we investigate the classical and quantum models of a flat energy-dependent FRW cosmology coupled to a perfect fluid in the framework of the scalar-rainbow…

General Relativity and Quantum Cosmology · Physics 2016-04-26 M. Khodadi , K. Nozari , B. Vakili

The relation of the Wigner function with the fair probability distribution called tomographic distribution or quantum tomogram associated with the quantum state is reviewed. The connection of the tomographic picture of quantum mechanics…

Quantum Physics · Physics 2015-06-19 Margarita A. Man'ko , Vladimir I. Man'ko